A process of manufacturing a semiconductor device includes a deposition process of forming a thin-film layer on a wafer and an etching process of forming a fine circuit pattern on the thin-film layer. Until a desired circuit pattern is formed on the wafer, these processes are repeated and, and after the circuit pattern is formed, many wrinkles may be generated on the surface of the wafer. Recently, as the semiconductor device has multiple layers with high integration, the number of wrinkles on the surface of the wafer and the height difference among them have increased. However, since the unevenness of the surface of the wafer may cause a problem such as defocusing in a photolithography process, regular polishing may be needed in order to make the surface of the wafer even.
There are various surface planarization technologies in order to make the surface of the wafer even. Among others, a chemical mechanical polishing apparatus is mostly used which may provide excellent evenness in a wide area in addition to a narrow area. The chemical mechanical polishing device includes a carrier head that applies pressure to a polishing pad while supporting the wafer.